Abstract

The causes of soft flesh in giant grenadier (Albatrossia pectoralis), an un-utilized species, and the means for improving its texture were investigated. The relationships of moisture and protein content, protease activity, and storage time to flesh softness were determined. Texture modification using physical methods (freeze-thaw cycles, osmotic moisture removal, static pressure, and centrifugal force) and injection of food additives (soy, whey and egg white proteins, starch, and gum) were evaluated.^ The softness of giant grenadier flesh was related to its high moisture and low protein content, averaging 91.4% and 6.8%, respectively, and its muscle structure. The ratio of water to protein was almost three times higher than other species. Compared to Alaska pollock, giant grenadier muscle consisted of large myotomes in loose bundles characteristic of soft fleshed fish. Protease activity was similar to Alaska pollock and not considered a factor in soft flesh.^ Seven freeze-thaw cycles moderately improved the firmness of giant grenadier fillets. The resulting fillets were slightly firmer than untreated fillets. Treatment of fillets in 90$\sp\circ$ SAL brine or dry salt for 4 hours significantly lowered moisture content improving texture that it compared favorably to flatfish. Static pressure of 20 kg for up to 4 hours was ineffective for improving texture. Sufficient pressure could not be applied without crushing muscle structure. Centrifugal force (125 x g$\rm\sb{m})$ applied for two hours removed almost 35% moisture and significantly firmed giant grenadier flesh. Fillets were judged as having texture similar to Dover sole.^ Injection of food proteins significantly improved texture of giant grenadier fillets. A soy protein solution at 7.5% and egg white at 15% effectively firmed fillets so they were comparable to Dover sole. Ten percent whey protein solutions produced slightly less firmness. Starch and gum solutions were not effective as texture enhancement additives for giant grenadier fillets.^ Comparison of dry salted and soy protein injected giant grenadier fillets with Dover sole during frozen storage showed slight texture improvement over a six month period. Giant grenadier fillets maintained texture while Dover sole fillets deteriorated, becoming very tough and undesirable. ^